JP5500381B2 - Power transmission shaft for vehicle steering system - Google Patents

Power transmission shaft for vehicle steering system Download PDF

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Publication number
JP5500381B2
JP5500381B2 JP2010209474A JP2010209474A JP5500381B2 JP 5500381 B2 JP5500381 B2 JP 5500381B2 JP 2010209474 A JP2010209474 A JP 2010209474A JP 2010209474 A JP2010209474 A JP 2010209474A JP 5500381 B2 JP5500381 B2 JP 5500381B2
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shaft
portion
torque
inner shaft
inner
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JP2012062991A (en
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雅芳 作田
要 城下
誠 野地
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株式会社ジェイテクト
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Description

  The present invention relates to a power transmission shaft for a vehicle steering apparatus.

The vehicle steering apparatus includes a power transmission shaft such as an intermediate shaft that transmits the rotation of the steering wheel to the pinion shaft of the rack and pinion mechanism. The intermediate shaft has a configuration that can be contracted in order to absorb an impact at the time of a vehicle collision (see, for example, Patent Document 1). The intermediate shaft of Patent Document 1 includes a hollow shaft and an insertion shaft that are fitted together.
Female serrations are formed on the inner periphery of the hollow shaft. A male serration that fits into the female serration is formed on the outer periphery of the insertion shaft. A recessed portion protruding radially inward is provided at one location on the circumference of the female serration of the hollow shaft. This depressed portion bites into the male serration of the insertion shaft. As a result, the female serration of the portion facing the depressed portion 180 degrees is pressed against the male serration of the insertion shaft. With this configuration, the hollow shaft and the insertion shaft are prevented from causing play (rattle) in the circumferential direction.

JP 10-45005 A

  In the above configuration, when a large impact force (excessive torque) acts on the intermediate shaft from the road surface via wheels or the like, the depressed portion of the female serration is pressed outward in the radial direction of the hollow shaft, so that the female serration is male serrated. Cause slipping. Once such a slip occurs, the depressed portion is disconnected from the male serration. As a result, the slip between the male selection and the female serration cannot be stopped, and there is a possibility that torque transmission by the intermediate shaft may be impossible. The state where torque cannot be transmitted through the intermediate shaft is a failure state, and is not a state where the vehicle is intended to run on its own. However, even if the intermediate shaft is in a failure state, the steered wheels of the vehicle are manipulated by operating the steering wheel even temporarily, such as when the vehicle is self-propelled to be transported to a maintenance shop and placed on a loaded vehicle. It is preferable from the viewpoint of improving the convenience of handling the vehicle.

  The present invention has been made based on such a background, and can suppress the occurrence of rattling during normal use, and can at least temporarily maintain a steering function even in the event of a failure, and a power transmission shaft for a vehicle steering apparatus. The purpose is to provide.

  To achieve the above object, the present invention provides an inner shaft (37) and a cylindrical outer shaft (38) fitted together, and a friction coupling member (39) interposed between the inner shaft and the outer shaft. The inner shaft includes a first shaft portion (41) and a second shaft portion (42) arranged in the axial direction (X1), and the outer shaft includes a first shaft portion through which the first shaft portion is inserted. 1 cylindrical part (51) and the 2nd cylindrical part (52) by which the said 2nd axial part was penetrated, The said 1st axial part opposes the radial direction (R1) of the said inner shaft. The first cylindrical portion includes a pair of regulated portions (44, 45), and the first cylindrical portion is a pair of regulation capable of regulating a relative rotation amount of the inner shaft and the outer shaft by engagement with the pair of regulated portions. Portions (54, 55; 54A, 55A), and the friction coupling member is configured to torque the second shaft portion and the second cylindrical portion with a predetermined friction torque (T1). It provides a vehicle steering apparatus (1) the power transmission shaft for characterized by (5) a that transmits linked (claim 1).

  According to the present invention, the inner shaft and the outer shaft are connected to each other with a predetermined friction torque so that torque can be transmitted by the frictional force of the friction connecting member. That is, the inner shaft and the outer shaft are frictionally engaged with the friction coupling member, and it is possible to suppress the occurrence of rattling (play) in the circumferential direction between the inner shaft and the outer shaft. Therefore, smooth torque transmission is possible between the inner shaft and the outer shaft. Further, when a large torque is input shockably between the inner shaft and the outer shaft, the inner shaft and the outer shaft may slip with respect to the friction coupling member, and the power transmission shaft may fall into a failure state. . However, since the friction coupling member is sandwiched between the inner shaft and the outer shaft, the state of being securely sandwiched between the inner shaft and the outer shaft is maintained. As a result, even if the power transmission shaft is in a failure state, the friction coupling member maintains a state where torque can be transmitted between the inner shaft and the outer shaft. Therefore, even if the power transmission shaft is in a failure state, the steering function can be maintained at least temporarily. In addition, when the relative rotation between the inner shaft and the outer shaft is restricted by the engagement between the pair of restricting portions and the pair of restricted portions, torque is transmitted through the pair of restricting portions and the pair of restricted portions. it can. As a result, since the load on the frictional connection member can be reduced, the durability of the frictional connection member can be increased, and steering using the frictional connection member can be maintained over a long period of time.

  In the present invention, the friction coupling member may include a tolerance ring having an annular corrugated shape (claim 2). In this case, the friction coupling member and the corresponding inner shaft and outer shaft can be brought into frictional contact at a number of locations in the circumferential direction of the inner shaft. Thereby, the load of each part of the friction coupling member can be leveled with respect to the circumferential direction of the inner shaft. As a result, since it can suppress that a local load acts on a frictional connection member, durability of a frictional connection member can be made higher.

In the present invention, torque can be transmitted between the inner shaft and the outer shaft by the cooperation of the pair of regulated portions and the pair of regulating portions and the friction coupling member. There is a case (Claim 3). In this case, since the load acting on the frictional connection member can be further reduced, the durability of the frictional connection member can be further increased.
In the present invention, the inner shaft includes a strength reducing portion (43) disposed between the first shaft portion and the second shaft portion, and a predetermined excessive torque exceeding the predetermined friction torque ( T2) When a larger torque acts on the inner shaft, the strength reducing portion may be made ruptureable (Claim 4). In this case, for example, when a large torque is applied to the power transmission shaft from the road surface via the steered wheels and the steered mechanism, the strength reducing portion is broken. Thereby, an intensity reduction part functions as a fuse, and it can control that a big load acts on other parts (gear etc. of a steering mechanism) of a vehicle steering device. Thus, as a result of being able to reliably define the portion that is damaged when an excessive torque is input to the steering device, the failure of the other portions can be suppressed, and the failure location of the vehicle steering device can be minimized.

Further, in the present invention, the regulated portions (54A, 55A) corresponding to the regulated portions (44, 45) are arranged apart from each other in the circumferential direction (C1) of the inner shaft. When the shaft and the outer shaft rotate relative to each other in the circumferential direction against the predetermined friction torque, each of the regulated portions and the corresponding regulating portion may be engageable (claim 5). ).
In this case, with respect to the torque below the predetermined friction torque, the torque can be transmitted between the inner shaft and the outer shaft only through the friction coupling member. Thus, contact between the pair of restricted portions and the pair of restricting portions can be suppressed until a torque exceeding a predetermined friction torque acts between the inner shaft and the outer shaft and the power transmission shaft fails. Therefore, it is possible to suppress a contact sound due to contact between the pair of regulated portions and the pair of regulating portions. Further, when a torque exceeding a predetermined friction torque acts between the inner shaft and the outer shaft, the friction coupling member slips with respect to the inner shaft or the outer shaft, resulting in a failure state. However, at this time, it is possible to prevent the relative rotation amount between the inner shaft and the outer shaft from becoming excessive due to the contact between the pair of regulated portions and the pair of regulating portions. Therefore, the load of the frictional connection member can be suppressed, and the torque transmission function by the frictional connection member can be more reliably maintained even when the power transmission shaft fails.

In the present invention, the friction coupling member may be arranged to be slidable with respect to at least one of the inner shaft and the outer shaft in the axial direction of the inner shaft.
In this case, when an impact along the axial direction is input to the power transmission shaft and the inner shaft and the outer shaft move relative to each other in the axial direction, the friction coupling member slides on at least one of the inner shaft and the outer shaft. To do. Thereby, an impact absorbing load can be generated. Therefore, for example, the impact on the driver when the driver collides with the steering member connected to the power transmission shaft (during the secondary collision) can be reduced.

  In addition, in the above, the numbers in parentheses represent reference numerals of corresponding components in the embodiments described later, but the scope of the claims is not limited by these reference numerals.

It is a schematic block diagram of the steering device which has an intermediate shaft as a power transmission shaft concerning one Embodiment of this invention. It is a disassembled perspective view of the principal part of an intermediate shaft. It is sectional drawing of an intermediate shaft, and has shown the state which looked at the intermediate shaft from the direction orthogonal to the central axis of an intermediate shaft. It is sectional drawing which follows the IV-IV line of FIG. (A) is a schematic diagram of the main part of the steering device, and shows a state where the vehicle is traveling straight ahead, and (B) shows a state where the vehicle is steered in the right direction. It is a schematic diagram of the principal part of a steering device, and shows a state where the strength reducing part is broken due to the vehicle riding on a curb or the like, and the direction of the steering member and the direction of the steered wheels are shifted accordingly. It is sectional drawing of the principal part for demonstrating operation | movement of the intermediate shaft at the time of a secondary collision. It is sectional drawing of the principal part of another embodiment of this invention. It is sectional drawing which follows the IX-IX line of FIG. (A) is a schematic diagram of the main part of the steering device, showing a state in which the vehicle rides on the curb, and (B) shows a state in which the relative rotation between the inner shaft and the outer shaft is restricted. Yes.

Preferred embodiments of the present invention will be described with reference to the accompanying drawings.
FIG. 1 is a schematic configuration diagram of a steering device as a vehicle steering device having an intermediate shaft as a power transmission shaft according to an embodiment of the present invention. Referring to FIG. 1, a steering apparatus 1 includes a steering shaft 3 connected to a steering member 2 such as a steering wheel, an intermediate shaft 5 as a transmission shaft connected to the steering shaft 3 via a universal joint 4, A pinion shaft 7 connected to the intermediate shaft 5 via a universal joint 6 and a rack shaft 8 as a steered shaft having a rack 8a meshing with the pinion 7a provided in the vicinity of the end of the pinion shaft 7 are provided. .

  A steering mechanism A1 is configured by a rack and pinion mechanism including the pinion shaft 7 and the rack shaft 8. The rack shaft 8 is supported by a housing 10 fixed to the vehicle body side member 9 so as to be movable in an axial direction along the left-right direction of the vehicle (a direction orthogonal to the paper surface). Although not shown, each end of the rack shaft 8 is connected to a corresponding steered wheel via a corresponding tie rod and a corresponding knuckle arm.

  The steering shaft 3 includes a first steering shaft 11 and a second steering shaft 12 that are connected coaxially. The first steering shaft 11 has an upper shaft 13 and a lower shaft 14 which are fitted so as to be able to rotate together and be slidable relative to each other in the axial direction using spline coupling. One of the upper shaft 13 and the lower shaft 14 constitutes an inner shaft, and the other constitutes a cylindrical outer shaft.

The second steering shaft 12 includes an input shaft 15 connected to the lower shaft 14 so as to be able to rotate together, an output shaft 16 connected to the intermediate shaft 5 through the universal joint 4, and the input shaft 15 and the output shaft 16 And a torsion bar 17 for connecting the two in a relatively rotatable manner.
The steering shaft 3 is rotatably supported by a steering column 20 fixed to the vehicle body side members 18 and 19 via a bearing (not shown).

The steering column 20 includes a cylindrical upper jacket 21 and a cylindrical lower jacket 22 that are fitted so as to be relatively movable in the axial direction, and a housing 23 connected to the lower end in the axial direction of the lower jacket 22. The housing 23 houses a speed reduction mechanism 25 that decelerates the power of the steering assisting electric motor 24 and transmits it to the output shaft 16.
The speed reduction mechanism 25 has a drive gear 26 that is connected to a rotation shaft (not shown) of the electric motor 24 so as to be able to rotate together with the drive gear 26 and a driven gear 27 that meshes with the drive gear 26 and rotates together with the output shaft 16. . The drive gear 26 is composed of, for example, a worm shaft, and the driven gear 27 is composed of, for example, a worm wheel.

  The steering column 20 is fixed to the vehicle body side members 18 and 19 via an upper bracket 28 on the vehicle rear side and a lower bracket 29 on the vehicle front side. The upper bracket 28 can be fixed to the upper jacket 21 of the steering column 20. The upper bracket 28 uses a fixing bolt (stud bolt) 30 that protrudes downward from the vehicle body side member 18, a nut 31 that is screwed to the fixing bolt 30, and a capsule 32 that is detachably held by the upper bracket 28. The vehicle body side member 18 is fixed.

The lower bracket 29 is fixed to the housing 23 of the steering column 20. Further, the lower bracket 29 is fixed to the vehicle body side member 19 using a fixing bolt (stud bolt) 33 protruding from the vehicle body side member 19 and a nut 34 screwed into the fixing bolt 33.
FIG. 2 is an exploded perspective view of the main part of the intermediate shaft 5. 1 and 2, the intermediate shaft 5 is formed by fitting an inner shaft 37 and a cylindrical outer shaft 38 so as to be slidable along the axial direction X1 and capable of transmitting torque. . One of the inner shaft 37 and the outer shaft 38 constitutes the upper shaft, and the other constitutes the lower shaft. In this embodiment, the outer shaft 38 is connected to the universal joint 4 as an upper shaft, and the inner shaft 37 is connected to the universal joint 6 as a lower shaft.

  In the present embodiment, the power transmission shaft is described as applied to the intermediate shaft 5, but the power transmission shaft of the present invention is applied to the first steering shaft 11, and the first steering shaft 11 has a telescopic adjustment function, You may make it fulfill | perform an impact absorption function. Further, in the present embodiment, the case where the steering device 1 is an electric power steering device will be described. However, the power transmission shaft of the present invention may be applied to a steering device for manual steering.

Referring to FIG. 2, the intermediate shaft 5 includes a rod-shaped inner shaft 37, a hollow outer shaft 38, and a tolerance ring 39 as a friction coupling member interposed between the inner shaft 37 and the outer shaft 38. Contains.
The inner shaft 37 is an integrally formed product formed by forging a metal material. The inner shaft 37 includes a first shaft portion 41, a second shaft portion 42, and a strength reducing portion 43 disposed between the first shaft portion 41 and the second shaft portion 42. The first shaft portion 41 is formed at one end 41 a of the inner shaft 37 adjacent to the outer shaft 38.

FIG. 3 is a cross-sectional view of the intermediate shaft 5 and shows a state in which the intermediate shaft 5 is viewed from a direction orthogonal to the central axis L <b> 1 of the intermediate shaft 5. 4 is a cross-sectional view taken along line IV-IV in FIG.
Referring to FIG. 4, the outer periphery 41 b of the first shaft portion 41 is formed in an oval shape when viewed along the axial direction X <b> 1 of the intermediate shaft 5 (inner shaft 37). A pair of to-be-regulated parts 44 and 45 facing the direction R1 and a pair of arcuate parts 46 and 47 facing the radial direction R1 are included. The regulated portions 44 and 45 and the arc-shaped portions 46 and 47 are alternately arranged in the circumferential direction C1 of the intermediate shaft 5.

  The pair of regulated portions 44 and 45 are each formed on a flat surface parallel to the axial direction X1. The pair of regulated portions 44 and 45 have a two-sided width W1 and are parallel to each other. The direction in which the pair of regulated portions 44 and 45 face each other and the direction in which the pair of arcuate portions 46 and 47 face each other are substantially orthogonal. The pair of arcuate portions 46 and 47 are formed on an arcuate surface centered on the central axis L <b> 1 of the inner shaft 37.

Referring to FIG. 2, the second shaft portion 42 has a larger shape than the first shaft portion 41 when viewed along the axial direction X1.
The second shaft portion 42 includes a tapered portion 49 adjacent to the first shaft portion 41 and a main body portion 50 extending from the tapered portion 49 along the axial direction X1. The tapered portion 49 has a truncated cone shape whose diameter increases with distance from the first shaft portion 41 along the axial direction X1. One end of the tapered portion 49 is connected to the strength reducing portion 43. The other end of the tapered portion 49 is connected to the main body portion 50. The main body 50 is formed in a cylindrical shape having a constant diameter.

The strength reduction unit 43 is provided to break when an unexpectedly large torque is input to the intermediate shaft 5. The large torque acts on the intermediate shaft 5 from the road surface via the steered wheels or the like, for example, due to the steered wheels riding on the curb while the vehicle is traveling.
The strength reducing portion 43 is formed thinner than the first shaft portion 41. The area when viewed along the axial direction X <b> 1 (cross-sectional area perpendicular to the axial direction X <b> 1) is smaller in the strength reducing portion 43 than in the first axial portion 41. The strength reducing portion 43 is formed in a substantially cylindrical shape. The radius of curvature of the strength reducing portion 43 is smaller than the radius of curvature of the arc-shaped portions 46 and 47 of the first shaft portion 41. The strength reducing portion 43 is disposed coaxially with the first shaft portion 41 and the second shaft portion 42.

One end of the strength reducing portion 43 is connected to the first shaft portion 41. The other end of the strength reducing portion 43 is connected to the second shaft portion 42. Regarding the axial direction X <b> 1, the length of the strength reducing portion 43 is shorter than the first shaft portion 41 and shorter than the second shaft portion 42.
The outer shaft 38 is an integrally molded product formed by forging a metal material or the like, and includes a first cylindrical portion 51 and a second cylindrical portion 52. The second cylindrical portion 52 is formed at one end 38 a of the outer shaft 38 adjacent to the inner shaft 37. The first tubular portion 51 is disposed on the other end side of the outer shaft 38 with respect to the second tubular portion 52. The 1st cylindrical part 51 and the 2nd cylindrical part 52 are adjacent to the axial direction X1.

  Referring to FIG. 4, the inner periphery 51 b of the first tubular portion 51 is formed in a shape that substantially matches the outer periphery 41 b of the first shaft portion 41 when viewed along the axial direction X1 of the intermediate shaft 5. ing. Specifically, the inner periphery 51b is formed in an oval shape, and a pair of restricting portions 54 and 55 facing the radial direction R1 of the intermediate shaft 5 and a pair of arc-shaped portions 56 facing the radial direction R1. , 57 and the like. The restricting portions 54 and 55 and the arc-shaped portions 56 and 57 are alternately arranged in the circumferential direction C1 of the intermediate shaft 5.

The pair of restricting portions 54 and 55 are capable of restricting relative rotation between the inner shaft 37 and the outer shaft 38 by engaging with the pair of restricted portions 44 and 45 and transmitting torque between the inner shaft 37 and the outer shaft 38. It is provided to connect to.
The pair of restricting portions 54 and 55 are each formed on a flat surface parallel to the axial direction X1. The pair of restricting portions 54 and 55 and the corresponding restricted portions 44 and 45 of the first shaft portion 41 have a slight gap (for example, about several μm) in the circumferential direction C1, and are substantially zero. Yes. In order to insert the first shaft portion 41 into the first tubular portion 51, the shape of the inner periphery 51b of the first tubular portion 51 is slightly larger than the shape of the outer periphery 41b of the first shaft portion 41. ing. When torque is applied to the intermediate shaft 5 in the initial state (the state when the vehicle is shipped from the factory), the inner shaft 37 and the outer shaft are brought into contact by the contact between the pair of restricting portions 54 and 55 and the corresponding restricted portions 44 and 45. Torque can be transmitted to and from 38.

The direction in which the pair of restricting portions 54 and 55 face each other and the direction in which the pair of arcuate portions 56 and 57 face each other are substantially orthogonal to each other. The pair of arcuate portions 56 and 57 are formed on an arcuate surface centered on the central axis L <b> 1 of the inner shaft 37.
Referring to FIG. 3, a first shaft portion 41 is inserted into the first tubular portion 51 so as to be relatively movable in the axial direction X1. Regarding the axial direction X <b> 1, the length of the first tubular portion 51 is longer than the length of the first shaft portion 41. In the initial state, a part of the first shaft portion 41 on the tip side is inserted into the first tubular portion 51. A peripheral edge portion 51c of the opening of the first cylindrical portion 51 is formed in an annular shape orthogonal to the axial direction X1.

  The 2nd cylindrical part 52 is formed in the cylindrical shape, and the 2nd axial part 42 is penetrated by the axial direction X1 so that relative movement is possible. The 2nd cylindrical part 52 has surrounded the 2nd axial part 42 over the perimeter. The 2nd cylindrical part 52 and the 2nd axial part 42 are arrange | positioned coaxially. One end of the second cylindrical portion 52 forms an opening that receives the inner shaft 37, and the other end of the second cylindrical portion 52 is connected to the outer diameter portion of the peripheral edge portion 51c.

  2 and 3, the tolerance ring 39 is provided to connect the second cylindrical portion 52 and the second shaft portion 42 so as to transmit torque by frictional force. The tolerance ring 39 is accommodated in the second cylindrical portion 52 and is interposed between the second cylindrical portion 52 and the second shaft portion 42. Thereby, the tolerance ring 39 is elastically compressed inward in the radial direction R1, and an elastic repulsive force along the radial direction R1 is generated. The tolerance ring 39 is a sheet metal member and has an annular corrugated plate shape. The tolerance ring 39 includes an annular main body portion 59 and a plurality of convex portions 60 protruding from the main body portion 59.

The main body 59 is formed in an annular shape. The main body 59 may be an endless ring having no cut in the circumferential direction C1, or may be a ring having an end in which a cut is formed in the circumferential direction C1. The main body 59 is in frictional contact with the outer periphery 42b of the second shaft portion 42 of the inner shaft 37 over the entire area in the circumferential direction C1.
The convex portion 60 is formed so as to protrude outward from the main portion 59 in the radial direction R1, for example. A plurality of convex portions 60 are arranged at equal intervals in the circumferential direction C <b> 1 to form a convex portion row 61. The convex row 61 includes, for example, at least four convex portions 60. A plurality (two in the present embodiment) of the convex row 61 is arranged along the axial direction X1. Each convex portion 60 is in frictional contact with the inner periphery 52 b of the second cylindrical portion 52 of the outer shaft 38.

  With reference to FIG. 3, the main part 59 of the tolerance ring 39 is elastically pressed by the outer periphery 42b of the 2nd axial part 42 over the whole region of the circumferential direction C1 by said structure. Each convex portion 60 of the tolerance ring 39 is elastically pressed against the inner periphery 52 b of the second cylindrical portion 52. As a result, the inner shaft 37 and the outer shaft 38 are connected by a tolerance ring 39 so that torque can be transmitted with a predetermined friction torque T1 (for example, several N · m). That is, a torque having the same value as the predetermined friction torque T1 can be transmitted between the inner shaft 37 and the outer shaft 38 through the tolerance ring 39 at the maximum. Further, the tolerance ring 39 is slidable in the axial direction X1 with respect to the outer periphery 42b of the second shaft portion 42 of the inner shaft 37, and on the inner periphery 52b of the second cylindrical portion 52 of the outer shaft 38. On the other hand, it can slide in the axial direction X1.

Next, the operation of the steering device 1 will be described.
As shown in FIG. 5A, which is a schematic diagram of the main part of the steering device 1, when the vehicle is traveling straight, the steering member 2 is located at the steering neutral position P1. The steering neutral position P1 refers to, for example, the position in the rotational direction of the steering member 2 when the spoke 2a of the steering member 2 extends along the vertical direction of the vehicle. At this time, the steered wheels 62L and 62R face the direction E1 along the substantially front-rear direction of the vehicle.

  From this state, when the driver rotates the steering member 2 clockwise in order to steer the vehicle to the right, for example, the torque (steering torque) applied from the driver to the steering member 2 is changed between the steering shaft 3 and the middle. It is transmitted to the steering mechanism A1 via the shaft 5 or the like. As a result, as shown in FIG. 5B, the rack shaft 8 is displaced from the position when the steering member 2 is at the steering neutral position P1 toward the right side of the vehicle, for example, and the steered wheels 26L and 26R are viewed in plan view. To rotate clockwise.

  At this time, in the intermediate shaft 5, the pair of restricting portions 54 and 55 of the outer shaft 38 are engaged with the corresponding restricted portions 44 and 45 of the inner shaft 37, and the tolerance ring 39 is The second cylindrical portion 52 and the second shaft portion 42 of the inner shaft 37 are in frictional contact. As a result, steering torque is transmitted from the outer shaft 38 to the inner shaft 37. That is, the outer shaft 38 and the inner shaft 37 are connected to each other so as to be able to transmit torque by the cooperation of the tolerance ring 39 and the pair of regulating portions 54 and 55 and the pair of regulated portions 44 and 45.

  Referring to FIG. 6, on the other hand, consider a case where one steered wheel 26L rides on (cursed) a curb stone 70, for example, when the vehicle is traveling straight ahead. In this case, the reaction force from the curb 70 acts on the intermediate shaft 5 via the steering mechanism A1 and the like, and a torque larger than a predetermined excessive torque T2 (for example, several hundred N · m) is applied to the intermediate shaft 5. May be entered. At this time, an extremely large torque acts between the pair of regulated portions 44 and 45 of the inner shaft 37 and the pair of regulating portions 54 and 55, and the strength reducing portion 43 of the inner shaft 37 breaks as shown in FIG. To do.

Thereby, torque transmission between the first shaft portion 41 and the first cylindrical portion 51 is interrupted. At this time, the inner shaft 37 rotates relative to the outer shaft 38, for example, several degrees in the circumferential direction C1 against the outer shaft 38 against frictional torque generated by the tolerance ring 39.
Thereby, even if the steering member 2 is positioned at the steering neutral position P1, the steered wheels 62L and 62R are directed in the direction E2 that is deviated from the direction E1 when the vehicle is traveling straight, and the vehicle does not travel straight. Therefore, the driver can be informed that the intermediate shaft 5 is broken and in a failure state. At this time, it is necessary to carry the vehicle to a maintenance factory by placing it on a loaded vehicle. At this time, the inner shaft 37 and the outer shaft 38 are connected by a tolerance ring 39 so that torque can be transmitted. Therefore, by operating the steering member 2, the steering torque of the steering member 2 can be transmitted to the steering mechanism A1 via the intermediate shaft 5 or the like. Thereby, the direction of the steered wheels 62L and 62R can be operated, and the vehicle can be mounted on the loaded vehicle by self-propelling.

  Further, as shown in FIG. 5A, consider a case where the vehicle collides with a wall or the like (primary collision) when the vehicle is traveling. In this case, a secondary collision in which the driver collides with the steering member 2 may occur due to the impact of the primary collision. At this time, if the impact on the steering member 2 is strong, as shown in FIG. 7, the outer shaft 38 is displaced toward the inner shaft 37 in one X2 of the axial direction X1, and the intermediate shaft 5 contracts. Thus, the tolerance ring 39 bites into the corresponding inner shaft 37 and outer shaft 38 while moving relative to at least one of the inner shaft 37 and the outer shaft 38 in the axial direction X1. For example, each convex portion 60 bites into the inner periphery 52 a of the second cylindrical portion 52. The impact on the driver is absorbed by the frictional resistance at this time.

As described above, according to the present embodiment, the inner shaft 37 and the outer shaft 38 are connected by the friction force of the tolerance ring 39 so as to be able to transmit torque with the predetermined friction torque T1. That is, the inner shaft 37 and the outer shaft 38 are frictionally engaged with the tolerance ring 39, and it is possible to suppress the rattling (play) between the inner shaft 37 and the outer shaft 38 in the circumferential direction C1.
Therefore, smooth torque transmission between the inner shaft 37 and the outer shaft 38 is possible. Further, when a large torque is input between the inner shaft 37 and the outer shaft 38, at least one of the inner shaft 37 and the outer shaft 38 slides with respect to the tolerance ring 39, and the intermediate shaft 5 falls into a failure state. There is. However, since the tolerance ring 39 is sandwiched between the inner shaft 37 and the outer shaft 38, the state in which the tolerance ring 39 is securely clamped between the inner shaft 37 and the outer shaft 38 is maintained. As a result, even if the intermediate shaft 5 is in a failure state, the tolerance ring 39 maintains a state where torque can be transmitted between the inner shaft 37 and the outer shaft 38. Therefore, even if the intermediate shaft 5 is in a failure state, the steering function can be maintained at least temporarily.

  Moreover, when the intermediate shaft 5 is not broken, the relative rotation between the inner shaft 37 and the outer shaft 38 is restricted by the engagement between the pair of restricting portions 54 and 55 and the pair of restricted portions 44 and 45. . Thereby, in addition to the tolerance ring 39, torque can be transmitted through the pair of restricting portions 54 and 55 and the pair of restricted portions 44 and 45. As a result, since the load on the tolerance ring 39 can be reduced, the durability of the tolerance ring 39 can be increased, and steering using the tolerance ring 39 can be maintained over a long period of time.

  In addition, a tolerance ring 39 having an annular corrugated plate shape is used as the friction coupling member. Thereby, the tolerance ring 39, the inner shaft 37, and the outer shaft 38 can be brought into frictional contact at a number of locations in the circumferential direction C1. Thereby, the load of each part of the tolerance ring 39 can be leveled regarding the circumferential direction C1. As a result, it is possible to suppress a local load from acting on the tolerance ring 39, so that the durability of the tolerance ring 39 can be further increased.

Further, during normal traveling, torque can be transmitted between the inner shaft 37 and the outer shaft 38 by the cooperation of the pair of regulated portions 44 and 45 and the pair of regulating portions 54 and 55 and the tolerance ring 39. Has been.
Thereby, since the load which acts on the tolerance ring 39 can be reduced more, durability of the tolerance ring 39 can be made higher. Therefore, rattling between the inner shaft 37 and the outer shaft 38 can be suppressed over a longer period.

  Further, when a torque larger than a predetermined excessive torque T2 acts on the inner shaft 37, the strength reducing portion 43 can be broken. For example, when a shocking large torque acts on the intermediate shaft 5 from the curbstone 70 on the road surface via the steered wheels 62L, the steered mechanism A1, and the like, the strength reducing portion 43 is broken. Thereby, the intensity reduction part 43 functions as a fuse, and it can suppress that an excessive load acts on the other parts (Pinion 7a, rack 8a, etc. of the steering mechanism A1). In this way, as a result of the fact that the portion that causes damage when a large torque is input to the steering device 1 can be reliably used as the strength reducing portion 43, the failure of the other portions can be suppressed, and the failure portion of the steering device 1 can be minimized. Can be.

Further, at the time of the secondary collision, when the impact along the axial direction X1 is input to the intermediate shaft 5 and the inner shaft 37 and the outer shaft 38 move relative to each other in the axial direction X1, the tolerance ring 39 moves to the inner shaft 37 and the outer shaft 37. Slide against at least one of the shafts 38. Thereby, an impact absorbing load can be generated. Therefore, the impact on the driver at the time of the secondary collision can be reduced.
FIG. 8 is a cross-sectional view of the main part of another embodiment of the present invention. 9 is a cross-sectional view taken along line IX-IX in FIG. In the following, differences from the above-described embodiment will be mainly described, and the same components are denoted by the same reference numerals and the description thereof will be omitted. Further, the state where the steering member 2 is positioned at the steering neutral position P1 will be described as a reference.

8 and 9, the intermediate shaft 5A of the present embodiment is different from the above-described intermediate shaft 5 mainly in that (1) the strength reducing portion 43 of the inner shaft 37 is abolished. (2) At normal times (when the intermediate shaft 5A is not broken down), the inner shaft 37 and the outer shaft 38 are connected through only the tolerance ring 39 so as to be able to transmit torque at two points. is there.
Regarding the difference (1), the first shaft portion 41 and the second shaft portion 42 of the inner shaft 37 are directly connected.

  Next, the difference (2) will be described. The first cylindrical portion 51 of the outer shaft 38 has a pair of restricting portions 54A and 55A. The pair of restricting portions 54A and 55A oppose each other in the radial direction R1 with the pair of restricted portions 44 and 45 of the inner shaft 37 interposed therebetween. The cross-sectional shape (the cross-sectional shape shown in FIG. 9) of the pair of restricting portions 54A and 55A is formed in a symmetric shape with respect to the opposing direction.

  Referring to FIG. 9, one restricting portion 54 </ b> A includes an angled portion 63 that protrudes toward the corresponding restricted portion 44. The mountain-shaped part 63 has a pair of inclined parts 63a and 63b. The inclined portions 63a and 63b are inclined at an equal angle in the opposite directions with respect to the adjacent regulated portion 44. The inclined portion 63a is separated from the regulated portion 44 by a predetermined angle D1 (for example, 5 degrees) in the circumferential direction C1. Similarly, the inclined portion 63b is separated from the regulated portion 44 by a predetermined angle D1 in the circumferential direction C1.

  The other restricting portion 55 </ b> A includes a mountain-shaped portion 64 that protrudes toward the corresponding restricted portion 45. The mountain portion 64 has a pair of inclined portions 64a and 64b. The inclined portions 64a and 64b are inclined at the same angle in opposite directions with respect to the adjacent regulated portion 45. The inclined portion 64a is separated from the regulated portion 45 by a predetermined angle D1 in the circumferential direction C1. Similarly, the inclined portion 64b is separated from the regulated portion 45 by a predetermined angle D1 in the circumferential direction C1.

With the above configuration, when the intermediate shaft 5A has not failed, the inner shaft 37 and the outer shaft 38 are connected by the tolerance ring 39 only so as to be able to transmit torque with a predetermined friction torque T1.
Next, the operation of the intermediate shaft 5A will be described.
Referring to FIG. 10A, for example, consider a case where one steered wheel 26L rides on curbstone 70 when the vehicle is traveling straight ahead. In this case, a torque larger than a predetermined friction torque T1 may be input to the intermediate shaft 5A via the steering mechanism A1. At this time, the inner shaft 37 rotates relative to the outer shaft 38 against the frictional torque caused by the tolerance ring 39, for example, by a predetermined angle D1 in the circumferential direction C1, and slips in the tolerance ring 39. The shaft 5A is in a failure state.

  At this time, as shown in FIG. 10 (B), the pair of restricted portions 44 and 45 of the first shaft portion 41 of the inner shaft 37 correspond to the inclined portions 63a corresponding to the pair of restricting portions 54A and 55A of the outer shaft 38. 63b, 64a, 64b (for example, inclined portions 63b, 64a) are engaged (contacted), and relative rotation between the inner shaft 37 and the outer shaft 38 is restricted. Accordingly, the pair of restricting portions 54A and 55A and the pair of restricted portions 44 and 45 are coupled so as to transmit torque with respect to one C2 in the circumferential direction C1.

  Referring to FIGS. 10A and 10B, at this time, when the intermediate shaft 5 rotates in the other direction C3 in the circumferential direction C1 due to the steering torque from the steering member 2, the pair of restricting portions 54A and 55A. In addition, torque is transmitted between the inner shaft 37 and the outer shaft 38 by the cooperation of the pair of regulated portions 44 and 45 and the tolerance ring 39. On the other hand, when the intermediate shaft 5 rotates in one direction C <b> 2 in the circumferential direction C <b> 1 due to the steering torque from the steering member 2, torque is transmitted between the inner shaft 37 and the outer shaft 38 via the tolerance ring 39.

  At this time, as shown in FIG. 10 (A), even if the steering member 2 is positioned at the steering neutral position P1, the steered wheels 62L and 62R are directed in the direction E2 that is deviated from the direction E1 when the vehicle is traveling straight. The vehicle does not travel straight ahead. Therefore, the driver can be notified that the intermediate shaft 5A is broken and in a failure state. At this time, it is necessary to carry the vehicle to a maintenance factory by placing it on a loaded vehicle. At this time, the inner shaft 37 and the outer shaft 38 are connected by at least a tolerance ring 39 so that torque can be transmitted. Therefore, by operating the steering member 2, the steering torque of the steering member 2 can be transmitted to the steering mechanism A1 via the intermediate shaft 5A or the like. Thereby, the direction of the steered wheels 62L and 62R can be operated, and the vehicle can be mounted on the loaded vehicle by self-propelling.

The operation of the intermediate shaft 5A when the inner shaft 37 of the intermediate shaft 5A rotates relative to the outer shaft 38 in the other direction C3 in the circumferential direction C1 by a predetermined angle D1 is the same as described above.
As described above, according to the present embodiment, with respect to the torque below the predetermined friction torque T1, it is possible to transmit the torque between the inner shaft 37 and the outer shaft 38 only through the tolerance ring 39. Thus, until a torque exceeding a predetermined friction torque T1 acts between the inner shaft 37 and the outer shaft 38 and the intermediate shaft 5 fails, the pair of regulated portions 44, 45 and the pair of regulating portions 54A, Contact with 55A can be suppressed. Therefore, it is possible to suppress the contact sound caused by the contact between the pair of restricted portions 44 and 45 and the pair of restricting portions 54A and 55A.

  Further, when a torque exceeding a predetermined friction torque T1 acts between the inner shaft 37 and the outer shaft 38, the tolerance ring 39 slips with respect to the inner shaft 37 and the outer shaft 38, resulting in a failure state. However, at this time, it is possible to suppress an excessive amount of relative rotation between the inner shaft 37 and the outer shaft 38 due to contact between the pair of regulated portions 44 and 45 and the pair of regulating portions 54A and 55A. Therefore, the load on the tolerance ring 39 can be suppressed, and the torque transmission function by the tolerance ring 39 can be more reliably maintained even when the intermediate shaft 5 is broken.

The present invention is not limited to the contents of the above embodiments, and various modifications can be made within the scope of the claims.
For example, the tolerance ring 39 may be held so as to be movable integrally with the inner shaft 37 or the outer shaft 38 in the axial direction X1. In this case, the tolerance ring 39 slides at the time of impact absorption with respect to the inner shaft 37 and the outer shaft 38 that can move relative to each other in the axial direction X1.

Moreover, you may use the tolerance ring from which a convex part protrudes inward of radial direction R1. In this case, in the tolerance ring, the main portion frictionally engages with the inner periphery 52b of the second cylindrical portion 52 of the inner shaft 37, and the convex portion frictionally engages with the outer periphery 42b of the second shaft portion 42 of the outer shaft 38. .
Moreover, although the tolerance ring 39 was illustrated as a frictional connection member, it is not limited to this. Instead of the tolerance ring 39, another member that frictionally engages both the outer periphery 42b of the second shaft portion 42 of the inner shaft 37 and the inner periphery 52b of the second tubular portion 52 of the outer shaft 38 may be used.

Moreover, although the strength reduction part 43 demonstrated the structure formed in a smaller diameter than the 1st axial part 41, it is not limited to this. The outer shape is the same as that of the first shaft portion 41, and a member formed using a material having a lower strength than the first shaft portion may be used as the strength reducing portion.
Further, the strength reducing portion 43 may be provided on the intermediate shaft 5A.
Moreover, you may apply this invention to power transmission shafts other than an intermediate shaft among vehicle steering devices.

  DESCRIPTION OF SYMBOLS 1 ... Steering device (vehicle steering device), 5 ... Intermediate shaft (power transmission shaft), 37 ... Inner shaft, 38 ... Outer shaft, 39 ... Tolerance ring (friction connecting member), 41 ... First shaft portion, 42 ... First Biaxial part, 43 ... Strength reducing part, 44, 45 ... Restricted part, 51 ... First cylindrical part, 52 ... Second cylindrical part, 54, 54A ... Restricting part, 55, 55A ... Restricting part, C1 ... Circumferential direction, R1 ... radial direction, T1 ... predetermined friction torque, T2 ... predetermined excessive torque, X1 ... axial direction.

Claims (6)

  1. An inner shaft and a cylindrical outer shaft fitted together,
    A friction coupling member interposed between the inner shaft and the outer shaft,
    The inner shaft includes a first shaft portion and a second shaft portion arranged in the axial direction,
    The outer shaft includes a first cylindrical part through which the first shaft part is inserted, and a second cylindrical part through which the second shaft part is inserted,
    The first shaft portion includes a pair of restricted portions facing in the radial direction of the inner shaft,
    The first cylindrical portion includes a pair of restricting portions capable of restricting a relative rotation amount of the inner shaft and the outer shaft by engagement with the pair of restricted portions,
    The power transmission shaft for a vehicle steering apparatus, wherein the friction coupling member couples the second shaft portion and the second cylindrical portion so as to transmit torque with a predetermined friction torque.
  2.   2. A power transmission shaft for a vehicle steering apparatus according to claim 1, wherein the friction coupling member includes a tolerance ring having an annular corrugated shape.
  3.   In Claim 1 or 2, torque can be transmitted between the inner shaft and the outer shaft by the cooperation of the pair of regulated portions and the pair of regulating portions and the friction coupling member. A power transmission shaft for a vehicle steering device.
  4. In any one of Claims 1-3, the said inner axis | shaft contains the intensity | strength reduction part arrange | positioned between the said 1st axial part and the said 2nd axial part,
    A power transmission shaft for a vehicle steering apparatus, wherein the strength reducing portion is ruptureable when a torque larger than a predetermined excessive torque exceeding the predetermined friction torque acts on the inner shaft.
  5.   In any one of Claims 1-4, the said control part corresponding to each said to-be-controlled part is arrange | positioned spaced apart in the circumferential direction of the said inner shaft, The said inner shaft and the said outer shaft are the said A power transmission shaft for a vehicle steering apparatus, wherein when the relative rotation is performed in the circumferential direction against a predetermined friction torque, each of the regulated portions can be engaged with the corresponding regulating portion.
  6. 6. The friction coupling member according to claim 1, wherein the friction coupling member is slidably arranged with respect to at least one of the inner shaft and the outer shaft in the axial direction of the inner shaft. A power transmission shaft for a vehicle steering device.
JP2010209474A 2010-09-17 2010-09-17 Power transmission shaft for vehicle steering system Expired - Fee Related JP5500381B2 (en)

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CN104797469B (en) * 2012-11-26 2017-03-08 日本精工株式会社 Transfer
DE102013221123A1 (en) * 2013-10-17 2014-11-06 Voith Patent Gmbh Flat pin connection for transmitting a torque and pin receptacle for such
JP6179765B2 (en) * 2013-10-30 2017-08-16 株式会社ジェイテクト An intermediate shaft, an intermediate shaft manufacturing method, and an electric power steering apparatus.
JP6364648B2 (en) * 2014-04-14 2018-08-01 三井金属アクト株式会社 Power door opener
JP6300090B2 (en) * 2014-05-30 2018-03-28 株式会社リコー Rotation drive transmission mechanism, fixing device, and image forming apparatus
JP6372455B2 (en) * 2015-09-07 2018-08-15 トヨタ自動車株式会社 Power transmission device for vehicle

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JPH0339624U (en) * 1989-08-29 1991-04-17
JPH05280546A (en) * 1992-04-02 1993-10-26 Kobe Steel Ltd Shaft coupling structure and shaft mounting/removing device
DE19518130C2 (en) * 1995-05-17 1997-05-15 Lemfoerder Metallwaren Ag Safety steering column of a motor vehicle
JP3617824B2 (en) * 2000-08-29 2005-02-09 三菱電機株式会社 Motor
JP2008137482A (en) * 2006-12-01 2008-06-19 Nsk Ltd Energy absorbing type intermediate shaft and its manufacturing method
JP5101357B2 (en) * 2008-03-18 2012-12-19 三菱重工業株式会社 Rotating machine and additional ring

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